This program represents a broad based clinical research program, with major emphasis on the development and application of new technology, and is a natural sequel to 5 years of previous work by the principal investigator and the co-investigators. Four major goals are as follows: I) Improving multiple gated equilibrium cardiac blood pool scintigraphy for assessment of left ventricular function; II) defining the role of assesment of left ventricular function by multiple gated equilibrium cardiac blood pool scintigraphy in evaluation of acute myocardial infarction; III) assessing right ventricular function by multiple gated equilibrium cardiac blood pool scintigraphy: multiple applications of a new technique; IV) improving assessment of regional myocardial perfusion by thallium-201 stress and redistribution myocardial scintigraphy. With respect to goal I, the present project will explore 1) the evaluation of the location and severity of coronary artery disease by assessment of the magnitude and location of regional dysfunction, 2) the quantification of abnormalities of regional left ventricular function and of left ventricular size, and 3) application of an inexpensive equilibrium probe method in assessment of exercise left ventricular function in the detection of coronary artery disease. For goal II, the project will evaluate five clinically important questions relating to left ventricular function in acute myocardial infarction. For goal III, a new technique developed in our laboratories for assessment of right ventricular function with equilibrium blood pool scintigraphy will be expanded and applied in a comprehensive group of clinical settings. For goal IV, the project will apply thallium-201 myocardial scintigraphy in evaluation of the location and severity of coronary artery disease 1) by assessment of the location of Tl-201 defects and by combination of segmental evaluation of both exercise Tl-201 and exercise multiple gated equilibrium cardial blood pool studies, 2) by evaluation of the rate of redistribution of Tl-201 defects, and by 3) application of inexpensive computerized tomographic Tl-201 imaging using a multiple pinhole collimator.